高压氧对脑缺血再灌注损伤后Cx37表达及血脑屏障的影响

目的:研究高压氧(HBO)对大鼠脑缺血再灌注(CIR)损伤后缝隙连接蛋白Cx37表达及血脑屏障(BBB)通透性的影响。方法:选用240只雄性Wistar大鼠,随机分成假手术组、模型组、模型+HBO组、HBO组各60只。采用线栓法制作大鼠大脑中动脉局灶性栓塞(MCAO)模型,并于再灌注1h、9h、21h、45h、69h进入HBO舱,期间行0.25MPa HBO治疗5次。在处死动物前1h经尾静脉注射2%伊文思兰(EB),采用比色法、实时荧光定量聚合酶链反应(RT-PCR)、Western Blot法分别检测CIR后0h、4h、12h、24h、48h、72h脑组织EB的含量、Cx37mRNA及蛋白的表达变化。结果:CIR损伤后不同时间点模型组与假手术组相比较脑组织EB的含量显著增高(P<0.01),其中EB的含量以CIR损伤后4h最为明显。模型+HBO组脑组织中EB的含量与同时间的模型组相比较显著降低(P<0.01),HBO组与同时间假手术组相比较脑组织中EB的含量变化不明显。Cx37mRNA及蛋白的表达与CIR损伤后0h相比于CIR损伤后4h、12h、24h、48h、72h表达显著增高(P<0.01),以CIR损伤后24hCx37mRNA及蛋白的表达增高最明显。CIR损伤后24h模型+HBO组与模型组相比较脑组织中Cx37mRNA及蛋白的表达水平明显减少(P<0.01);CIR损伤后24hHBO组与假手术组相比脑组织中Cx37mRNA及蛋白的表达变化差异无统计学意义。结论:高压氧可以降低脑缺血再灌注后BBB通透性,其保护作用与抑制缝隙连接蛋白Cx37的表达有关。

Effects of hyperbaric oxygen on expression of gap junctional protein Cx37 in brain and blood brain barrier after cerebral ischemia-reperfusion in rats

Objective: To investigate the effects of hyperbaric oxygen (HBO) on the expression of gap junctional protein Cx37 in the brain and blood brain barrier (BBB) after cerebral ischemia reperfusion (CIR) in rats. Methods: 240 male Wistar rats were randomly assigned into sham operation, model, model+HBO, and HBO groups (n=60 each). Using CIR models, 0.25 MPa HBO was applied 5 times during the reperfusion period, and 2% Evens blue (EB) was injected into tail veins 1 h before the animals were executed. The expression of Cx37 mRNA and protein, and the contents of EB were determined by RT-PCR, Western blotting and spectrophotometer, respectively. Results: In model group, the EB content in brain tissue was significantly increased as compared with the sham operation group, reaching its peak at 4 h post CIR injury (P<0.01). The expression of Cx37 mRNA and protein significantly increased consecutively in different model group as compared with the 0 h group, reaching its highest level at 24 h. There was no significant difference in the expression of Cx37 mRNA and protein, and the content of EB between HBO group and sham operation group (P>0.05). The expression of Cx37 mRNA and protein in model+HBO group at CIR 24 h was significantly decreased as compared with model group (P<0.01). Conclusion: HBO intervention can decrease the permeability of BBB via reducing the expression level of Cx37 mRNA and protein.